Propeller Selection - Mercury 140 Service Manual

INSTALLATION

Propeller Selection

For best all around performance from your outboard/boat combination, select a propeller that allows the engine to
operate in the upper half of the recommended full throttle RPM range with the boat normally loaded (refer to General
Information - Specifications). This RPM range allows for better acceleration while maintaining maximum boat
speed.
ob00323
If changing conditions cause the RPM to drop below the recommended range, such as warmer, more humid
weather, operation at higher elevations, increased boat load, or a dirty boat bottom/gearcase, a propeller change
or cleaning may be required to maintain performance and ensure the outboards durability.
Check full-throttle RPM, using an accurate tachometer, with the engine trimmed out to a balanced-steering
condition (steering effort equal in both directions) without causing the propeller to break loose.
20